Background In traditional medicine, the maceration of seeds of Garcinia kola (GK) is used to treat various diseases including diabetes. In traditional pharmacopoeia, GK seeds are used to strengthen the immune system and as a stimulant and aphrodisiac. Aims This study aimed to evaluate the antidiabetic free radical scavenging effects of the hydroalcoholic extract of GK seeds (HAEGS) in a dexamethasone-induced hyperglycemic (DexIH) rat model. Settings and Design This study was an interventional study. Subjects and Methods Here using in vivo model, we assessed some pharmacological properties of HAEGS in DexIH rat. Hypoglycemia, antihyperglycemia, spasmolytic and laxative activities were also evaluated in DexIH. In vitro study assessed antiradical activity. The HAEGS was obtained by decoction introducing 250 g with water–ethanol mixture (30:70). The plant extract was administered to the animals at doses of 50 (GK50) and 100 (GK100) mg/kg body weight. All animal experiments were in accordance with ARRIVE guidelines and were performed in accordance with the scientific procedures of UK Animals. Antiradical activity of GK was assessed in vitro by inhibition of the activity of 2,2-diphenyl-1-picrylhydrazyl. Statistical Analysis Used Statistical analysis was performed using GraphPad Prism 5.03 software, and P values less than 0.05 were considered statistically significant. Results At doses 50 and 100 mg/kg, GK significantly ( P < 0.001) regulated DexIH after two weeks of treatment compared to the normoglycemic control and hyperglycemic rats. The extract at both doses significantly ( P < 0.001) inhibited the spasmolytic activity in both normoglycemic and hyperglycemic rats compared to Imodium ® . In rats DexIH rats, only dose 100 mg/kg significantly ( P < 0.05) increased laxative effects when compared to the negative control. In vitro antiradical activity of GK revealed vitamin C-like antiradical activity. Conclusions This study justifies the traditional use of GK seeds as an antidiabetic.

Introduction the leaves of Vernonia amygdalina (V. amygdalina) are consumed as food in sub-Saharan Africa (SSA). In traditional medicine, this plant is widely used in the treatment of cancer and diabetes mellitus. In the present study, we evaluated the antihyperglycemic and the antiproliferative activities of the hydroalcoholic extract of V. amygdalina leaves (HAEVa). Methods we conducted an experimental descriptive and analytical study with a prospective data collection from May 2019 to July 2020. For the in vivo study, the experiments were carried out on albino male rats of Wistar strain (Rattus norvegicus). Antihyperglycemic activity was performed in vivo in dexamethasone-induced insulin-resistant rats using the oral glucose tolerance test (OGTT). The biocompatibility and the antiproliferative activity of extract were performed in vitro respectively on rabbit primary dermal fibroblasts (RPDF) and human osteosarcoma MG-63 cells using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The data were analyzed with the GraphPad Prism software version 5.0.3. The statistical analyses were obtained by the analysis of variance (ANOVA), followed by Bonferroni´s post-test. P<0.05 was considered as the minimal level of statistical significance. Results regarding to the antiproliferative investigation, extract at 125, 250 μg/mL exhibited a significant cytotoxic effect on human osteosarcoma MG-63 compared to the vehicle (p<0.001) in a dose-response manner after 24h, 48h of exposure to HAEVa. Interestingly, HAEVa in concentrations of 125 and 250μg/ml showed no cytotoxicity (p>0.05) on RPDF after the different times of exposure. However, HAEVa in a high concentration of 500 μg/mL wasn´t biocompatible with RPDF. HAEVa also prevented postprandial blood glucose level in dexamethasone-induced insulin-resistant rats at both doses tested (p>0.05 and p<0.01 at doses of 50 and 100 mg/kg respectively). Conclusion the results of this study suggest that HAEVa has antiproliferative properties on MG-63 osteosarcoma in vitro and also inhibits in vivo the postprandial blood glucose level in dexamethasone-induced insulin-resistant rats.